This is phase-1 of switching from llvm::Optional to std::optional in the
next rebranch. llvm::Optional was removed from upstream LLVM, so we need
to migrate off rather soon. On Darwin, std::optional, and llvm::Optional
have the same layout, so we don't need to be as concerned about ABI
beyond the name mangling. `llvm::Optional` is only returned from one
function in
```
getStandardTypeSubst(StringRef TypeName,
bool allowConcurrencyManglings);
```
It's the return value, so it should not impact the mangling of the
function, and the layout is the same as `std::optional`, so it should be
mostly okay. This function doesn't appear to have users, and the ABI was
already broken 2 years ago for concurrency and no one seemed to notice
so this should be "okay".
I'm doing the migration incrementally so that folks working on main can
cherry-pick back to the release/5.9 branch. Once 5.9 is done and locked
away, then we can go through and finish the replacement. Since `None`
and `Optional` show up in contexts where they are not `llvm::None` and
`llvm::Optional`, I'm preparing the work now by going through and
removing the namespace unwrapping and making the `llvm` namespace
explicit. This should make it fairly mechanical to go through and
replace llvm::Optional with std::optional, and llvm::None with
std::nullopt. It's also a change that can be brought onto the
release/5.9 with minimal impact. This should be an NFC change.
Correct format:
```
//===--- Name of file - Description ----------------------------*- Lang -*-===//
```
Notes:
* Comment line should be exactly 80 chars.
* Padding: Pad with dashes after "Description" to reach 80 chars.
* "Name of file", "Description" and "Lang" are all optional.
* In case of missing "Lang": drop the "-*-" markers.
* In case of missing space: drop one, two or three dashes before "Name of file".
In order for Xcode to use these completions, we complete "?.member" when the
user has typed "anOptional.", but we also say that in order to apply this
result, N bytes to the left of the cursor should be erased first.
rdar://16579657 rdar://15233283
Swift SVN r16409
ASTContexts
This introduces swift::ide::CodeCompletionCache, which is a persistent code
completion result cache.
Right now REPL happens to use it (try importing Cocoa and doing code
completion), and the difference is noticeable. But completion in REPL is
still slow, because Cocoa goes through the AST Verifier on every completion
(for unknown reasons).
This commit does not implement cache invalidation yet, and it does not use
libcache to evict cache entries under memory pressure.
This commit also introduces two regressions:
- We get fewer Cocoa results that expected. Module::isModuleVisible in Clang
does not incorrectly reports that that ObjectiveC.NSObject submodule is not
visible from Cocoa.
- We are not implementing the decl hiding rules correctly. We used to rely on
visible decl lookup to do it for us, but now we have a different data structure
we have real decls from the current module and we have a text-only cache, so we
are forced to reimplement this part of name lookup in code completion.
Swift SVN r9633
